3412 AGRICULTURE. 



The amount of copper sulphate used depends 

 upon the strength of the mixture desired, three 

 pounds being sufficient for peach-trees in foliage, 

 and six pounds being harmless to dormant trees. 

 Dissolve the copper sulphate in an earthen jar 

 or wooden pail by suspending it in a sack so 

 that it will just touch the water. Hot or cold 

 water may be used. Slake the lime, and after 

 it is done slaking add water enough to make a 

 thin paste ; strain this through a gunny-sack 

 into a vessel containing twenty-five gallons of 

 water, and stir thoroughly. Mix together the 

 lime and copper sulphate solutions in equal 

 parts. 



It is well to add a little of one of the arsenical 

 sprays, since by so doing one may kill both 

 insects and fungi at the same time. It is better 

 to use the Bordeaux mixture when fresh. It 

 should be applied in dry weather, if possible. 



Bordeaux solution containing free copper 

 sulphate is injurious to foliage and blossoms.* 

 It should always be tested with potassium ferro- 

 cyanide.f 



Directions for testing : 



{a) In a test tube or bottle make a Bordeaux solution 

 with an excess of lime and add a few drops of potas- 

 sium ferrocyanide. Note change. 



*See Bulletin 287, New York Experiment Station, 

 f Potassium ferrocyanide is very poisonous. Handle with 

 care. Label ''Poison." 



